SOLUTION: logbase10 x +logbase10 (x+21) = 2

Question 261362: logbase10 x +logbase10 (x+21) = 2
Answer by stanbon(75887) (Show Source): You can put this solution on YOUR website!
logbase10 x +logbase10 (x+21) = 2
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log(x) + log(x+21) = 2
---
log[x(x+21)] = 2
---
x(x+21) = 10^2
x^2+21x-100 = 0
(x+25)(x-4) = 0
Positive solution:
x = 4
====================
Cheers,
Stan H.
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